D. Karagiannis, R. Maartens, J. C. Fonseca, S. Camera, C. Clarkson
Abstract
The power spectrum and bispectrum of dark matter tracers are key and complementary probes of the Universe. Next-generation surveys will deliver good measurements of the bispectrum, opening the door to improved cosmological constraints and the breaking of parameter degeneracies, from the combination of the power spectrum and bispectrum. Multi-tracer power spectra have been used to suppress cosmic variance and mitigate the effects of nuisance parameters and systematics. We present a bispectrum multi-tracer formalism that can be applied to next-generation survey data. Then we perform a simple Fisher analysis to illustrate qualitatively the improved precision on primordial non-Gaussianity that is expected to come from the bispectrum multi-tracer. In addition, we investigate the parametric dependence of conditional errors from multi-tracer power spectra and multi-tracer bispectra, on the differences between the biases and the number densities of two tracers. Our results suggest that optimal constraints arise from maximising the ratio of number densities, the difference between the linear biases, the difference between the quadratic biases, and the difference between the products b1bΦ for each tracer, where bΦ is the bias for the primordial potential.
Keywords
cosmological parameters from LSS; galaxy surveys; inflation; power spectrum; Astrophysics - Cosmology and Nongalactic Astrophysics
Journal of Cosmology and Astroparticle Physics
Volume 2024, Issue 034
2024 March
